This invention relates generally to medical devices and more particularly to flexible, power-driven catheters for intravascular surgery and other surgical procedures.
Heretofore, the only interventional methods for treating atherosclerotic disease involves surgery for bypassing or remolding obstructive atherosclerotic material. Lasers have been suggested and are under investigation for transluminal revascularization. However, such devices have not been found common acceptance in medical practice because of various technical difficulties, the most serious of which being their tendency to perforate arterial tissue.
In U.S. Pat. No. 4,445,509 (Auth) there is disclosed a recanalization catheter designed specifically for cutting away hard, abnormal deposits, such as atherosclerotic plaque, from the inside of an artery, and while supposedly preserving the soft arterial tissue. That recanalization catheter includes a sharp edged, multi-fluted, rotary cutting tip mounted at the distal end of the catheter and arranged to be rotated by a flexible drive shaft extending down the center of the catheter. The rotation of the cutting head is stated as producing a "differential cutting" effect whereupon relatively hard deposits are cut away from relatively soft tissue. Suction ports are provided in the cutting tips to pull the hard particles produced by the cutting action into the catheter for removal at the proximal end thereof so that such particles do not flow distally of the catheter where they could have an adverse effect on the patient's body.
It has been determined that the use of sharp rotary cutting blades in a revascularization catheter can have various adverse effects on the arterial tissue, e.g., snagging, cutting or otherwise damaging the tissue of the artery wall.